U.S. patent number 3,932,966 [Application Number 05/561,896] was granted by the patent office on 1976-01-20 for abrasive disc.
This patent grant is currently assigned to Bill Peter Philip Nederman. Invention is credited to Leif E. Stern.
United States Patent |
3,932,966 |
Stern |
January 20, 1976 |
Abrasive disc
Abstract
An abrasive disc which may be attached to a holder having a
suction device associated therewith. The disc includes a body of
soft, resilient material and abrasive layers on both sides.
Apertures, openings, and orifices in the abrasive layers and in the
edge of the body allow air and particles to be drawn into internal
passages in the body of the disc and flow out of the body to the
suction device in the holder. The apertures also facilitate
attachment of the abrasive disc to the holder.
Inventors: |
Stern; Leif E. (Uppakra,
SW) |
Assignee: |
Nederman; Bill Peter Philip
(Helsingborg, SW)
|
Family
ID: |
26656468 |
Appl.
No.: |
05/561,896 |
Filed: |
March 25, 1975 |
Foreign Application Priority Data
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Mar 26, 1974 [SW] |
|
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74040247 |
Sep 17, 1974 [SW] |
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74116674 |
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Current U.S.
Class: |
451/488;
451/359 |
Current CPC
Class: |
B24D
9/08 (20130101); B24D 13/14 (20130101) |
Current International
Class: |
B24D
13/14 (20060101); B24D 9/08 (20060101); B24D
9/00 (20060101); B24D 13/00 (20060101); B24B
055/02 (); B24B 023/00 () |
Field of
Search: |
;51/356,358,17R,17T,17TL,17MT,273,275 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Simpson; Othell M.
Attorney, Agent or Firm: Bacon & Thomas
Claims
I claim:
1. An abrasive disc which has an interior through which air and
particles may flow and which is adapted to be detachably secured to
a holder having pins projecting therefrom and a suction device
associated therewith, the abrasive disc comprising:
a. a body of soft, resilient material having oppositely facing
sides and an edge therebetween;
b. a first abrasive layer on one side of said body;
c. a first set of grooves in said body on at least said one side
thereof, said abrasive layer extending across said grooves;
d. a first set of openings in said edge;
e. a first set of apertures in said first abrasive layer, said
openings and said apertures being connected with said grooves;
f. whereby, in operation, air and particles may be drawn into said
apertures and openings, through said grooves, and toward the
suction device.
2. An abrasive disc as defined in claim 1 including:
a. a second abrasive layer on the other side of said body;
b. a second set of grooves in said body on said other side thereof,
said second abrasive layer extending across said second set of
grooves;
c. a second set of openings in said edge;
d. a second set of apertures, said second set of apertures being
formed in said second abrasive layer, said second set of openings
and said second set of apertures being connected with said second
set of grooves.
3. An abrasive disc as defined in claim 2 wherein said apertures
are adapted for an interference fit with the pins of the holder,
portions of the abrasive layer immediately adjacent said apertures
being folded inwardly from the exterior of the abrasive disc around
said apertures when the abrasive disc is attached to the holder,
said inwardly folded portions being adapted to abrasively engage
the pins of the holder to secure the abrasive disc to the
holder.
4. An abrasive disc as defined in claim 2, including a plurality of
holes in said body, said holes being adapted to receive the pins of
the holder therein, each of said holes intersecting one groove of
said first set of grooves and one groove of said second set of
grooves, whereby, in operation, at least one said sets of grooves
is open for communication with its associated set of openings and
apertures even when the pins of the holder are inserted into said
holes.
5. An abrasive ddisc as defined in claim 4, wherein each of said
holes completely surrounds its associated groove at a particular
location along each groove, whereby, in operation, the pins of the
holder block the grooves of the other of said sets of grooves.
6. An abrasive disc as defined in claim 4, wherein said sets of
apertures are aligned with said holes and are smaller in diameter
than said holes.
7. An abrasive disc as defined in claim 6, wherein each abrasive
layer includes a portion immediately surrounding each of said
apertures, each portion being inwardly foldable into said holes in
response to engagement of said apertures with the pins of the
holder, each of said portions having abrasive material thereon for
effecting a secure grip on the pins.
8. An abrasive disc as defined in claim 2:
a. including a plurality of bores for effecting communication
between the interior of the abrasive disc and the suction
device;
b. wherein the grooves of said sets of grooves extend radially in
said body, the distance between two adjacent grooves exceeding the
width of each groove;
c. including first and second annular channels in said body, said
first annular channel being disposed on one side of said body, said
second annular channel being disposed on the other side of said
body, said first set of grooves being connected with said first
annular channel, said second set of grooves being connected with
said second annular channel;
d. said bores intersecting said annular channels;
e. first and second sets of orifices in said abrasive layers, said
sets of orifices being disposed radially inwardly of said sets of
apertures, said orifices of said first set being disposed in said
first abrasive layer, said orifices of said second set being
disposed in said second abrasive layer, said first set of orifices
communicating with said first annular channel and said bores, said
second set of orifices communicating with said second annular
channel and said bores;
f. whereby, in operation, one of said sets of orifices allows air
and particles to flow from the interior of said body to the suction
device and the other set of orifices provides an additional inlet
for air and particles to flow into the interior of said body.
9. An abrasive disc as defined in claim 8 including a ring engaging
an outer surface of one abrasive layer said ring having an inner
edge disposed radially outwardly of said orifices.
10. An abrasive disc as defined in claim 1, wherein said body
comprises an expanded material.
11. An abrasive disc as defined in claim 10, wherein said expanded
material is an expanded plastic material such as styrene.
Description
BACKGROUND AND OBJECTS
1. Field of the Invention
The present invention relates to an abrasive disc which may be
readily fixed on a holder. The disc is stabilized on the holder by
means of pins projecting from the holder, and these pins also allow
for easy removal of the disc from the holder. The abrasive disc is
provided with apertures for sucking air up and grinding particles
by means of a suction device.
2. Description of the Prior Art
Abrasive discs with apertures for sucking up air and grinding
particles are expensive to produce, since the passages extending
within said discs substantially complicate the process of
manufacturing. Consequently, the discs are provided only with few
passages, said discs are permanently secured on a holder and the
grinding paper is exchanged in regular intervals. The grinding
paper is fastened with a pressure sensitive glue, but the paper is
easily unglued because of grinding particles becoming wedged in
under the paper during operation.
OBJECTS OF THE INVENTION
It is an object of the present invention to provide a grinding
device of the abovementioned type, which is inexpensive to produce
despite a plurality of passages, which permits a stable fixing of
grinding paper or the like, which permits easy mounting on the
holder, stable fixing on said holder and quick demounting from the
holder, and which allows for two opposed sides of the same to be
used for grinding.
SUMMARY OF THE INVENTION
The foregoing difficulties in the prior art are overcome and the
foregoing objects are achieved by providing an abrasive disc
including a body of soft, resilient material having oppositely
facing sides and an edge therebetween, a first abrasive layer and a
first set of grooves on one side of the body, the abrasive layer
extending across the grooves, a first set of openings in the edge,
a first set of apertures in the first abrasive layer, the openings
and apertures being connected with the grooves, whereby, in
operation, air and particles may be drawn into openings and
apertures, through the grooves and toward a suction device
associated with the holder for the disc. According to more detailed
aspects of the invention, there may be a second abrasive layer
having a set of apertures on the other side of the disc, and second
sets of openings and grooves. Either of the sets of apertures may
be used in fastening the disc to its holder. In this regard,
portions of the abrasive layer immediately adjacent the apertures
are inwardly foldable in response to engagement with pins extending
from the holder. These portions will abrasively engage the pins to
secure the abrasive disc to the holder.
DRAWINGS
The invention will be further described below with reference to the
accompanying drawings in which;
FIG. 1 shows the abrasive disc according to the invention from
underneath and partly in section;
FIG. 2 is a section through the abrasive disc arranged on a
holder;
FIG. 3 is a section through a portion of the abrasive disc before
it is mounted on the holder and finally;
FIG. 4 is a section through said portion of the abrasive disc after
its mounting on the holder.
DESCRIPTION
The abrasive disc 1, which is to be described in more detail
hereinafter, is designed to be arranged on a driven holder 2 and
cooperate with a suction device (not shown). In FIG. 2, the holder
2 is in the form of a plate with projecting pins 3. The plate is
supported by a ring 4 connected thereto, and is rotated and
oscillated by means of a drive shaft 5 via an eccentric body 6 and
a ball bearing 7. A housing 8 is placed above the plate of the
holder 2, said housing having a connection piece 9 for connection
to the suction device. When the abrasive disc 1 securedly securedly
pressed on the plate 2, passages in the abrasive disc are
communicating with the suction device via holes 10 in the plate 2,
via the interior of the housing 8 and via the connection piece
9.
According to the invention, the abrasive disc 1 may easily be
pressed on and attached to the holder 2 with any one of its opposed
sides against the holder. After the pressing the abrasive disc 1
shall be fixedly secured on the holder and easy removable from the
same, e.g. for being turned and pressed onto the holder with the
abrasive for the grinding directed against the holder. Further, the
abrasive disc must provide a stable securing of the abrasive, the
abrasive disc shall be inexpensive to produce so that it may be
thrown away after wearing out the abrasive and the abrasive disc
must provide effective grinding particle collecting properties.
In order to accomplish this, the abrasive disc 1 according to the
invention comprises a body 12 of a soft, resilient material,
preferably expanded material, such as styrene. On two opposed sides
12a, 12b, an abrasive layer 11a, 11b is attached by, for example,
glueing on each side respectively. The layers have greater density
than the body 12. The opposed sides 12a, 12b of the body 12 are
provided with grooves 14a, 14b. These grooves are covered by the
abrasive layers respectively and to define passages which open
against an edge 12c extending between the sides 12a, 12b of the
body. Grooves 14a and 14b also open against the sides of the
abrasive layers by means of apertures 15, 16 in said layers
respectively and are connected to the suction device. The grooves
14a or 14b are placed beside each other at a distance somewhat
exceeding the width of the grooves. This means that there are at
least 32 air intakes provided in the preferred embodiment in the
drawings.
If the pins 3 are sufficiently pointed (pointed pins not shown)
they may be forced through the abrasive layers 11a, 11b,
respectively and forced into the soft, resilient material of the
body 12. Thus, the edges around every hole made by the pins 3 in
the abrasive layers are bent inwardly so that the abrasive grains
on each abrasive layer 11a, 11b engage the pins respectively.
Consequently, displacement of the abrasive disc 1 on the pins 3 is
effectively prevented, i.e. the abrasive is fixedly secured on the
holder 2 during rotation and oscillation thereof. If desired, the
abrasive disc is easily removable for turning or replacement with
another disc, e.g. a disc having another size on the abrasive
grains of the abrasive layer.
In order to provide a similar secure mounting of the abrasive disc
1 on the holder 2 and also to prevent disturbance of the air
flowing in the disc, the body 12 is provided with holes 13
corresponding to the pins 3. The grooves 14a, 14b are connected to
these holes 13 i.e. air flows streaming through the grooves must
also pass through the holes 13. The pins 3 extend independently of
the direction from which they are inserted in the holes 13 of the
body 12, down through said holes 13 at least partially and
preferably totally blocking the grooves 14a or 14b (14b in FIG. 2)
under the abrasive layer 11a or 11b (11b in FIG. 2) lying closest
to the holder 2 while leaving open the grooves 14a or 14b (14a in
FIG. 2) under the abrasive layer 11a or 11b (11a in FIG. 2) turned
away from the holder 2. Thus, the pattern of the air flow will be
as follows see FIG. 2), Air is sucked in through apertures of the
grooves 14a and openings in the edge 12c, passes the apertures 15,
and through these taking up grinding particles, passes the annular
channel 17a of two annular channels 17a, 17b extending in the
opposed sides of the body 12, passes bores 18 and thereby (and/or
when passing the annular channel 17a) passing orifices 19a in the
abrasive layer 11a and through these orifices 19a taking up
grinding particles. The air flow thereafter passess through the
bores 18, without disturbance from air entering through the grooves
14b. The air also flows via orifices 119a in the abrasive layer 11b
to the holes 10 in the holder 2 and, via these holes 10, to the
interior of the housing 8 and the connection piece 9 to the suction
device.
In order to ensure substantial adherence between the abrasive disc
1 and the holder 2, the apertures 15, 16 in the abrasive layers
11a, 11b may be considerably less in size than the holes 13 beyond
said apertures 15, 16. This means that the portions 11c, 11d
overlapping the holes 13 in the body 12 are folded into the holes
13 when the pins 3 are forced in through said holes (see FIGS. 3
and 4).
Accordingly the abrasive grains on the portions 11d (and when the
disc is turned, the abrasive grains on the portions 11c) will
define a friction lining in the holes 13 for the pins 3.
To eliminate the risk that the holes in the abrasive disc do not
communicate with the holder 2, said holder may be provided with a
ring 20 (e.g. of a rubber material) of which the inner edge 20a
lies outside the orifices 19a, 19b (19b in FIG. 2) in the abrasive
layers 11a, 11b (11b in FIG. 2). This insures that a slit is formed
between the disc 1 and the holder 2, through which slit air may
flow obliquely, if necessary.
In order to create, for example three rows of grinding particle
intakes (15, 16, 19a in FIG. 1) in each abrasive layer, the pins 3
may be arranged in two rows, whereby the pins 3 in one row are
laterally displaced in relation to the pins 3 in the other row.
When describing the preferred embodiment, certain alternatives have
been referred to. However, it is possible to define other
sub-assemblies not mentioned here but within the scope of the
present invention. For example the pins 3 may be hollow and define
percolation passages.
* * * * *